Plantoids: Amazing Robots That Actually Grow!

European researchers for the Plantoid Project are currently working on building robots with the ability to grow.

[Credit: The Plantoid Project]

The Plantoid Project aims to create robots that imitate many of the properties of plant roots, including the ability to create its own mass, primarily for the purpose of soil monitoring. According to the project's mission statement, the robots will be "endowed with distributed sensing, actuation, and intelligence for tasks of environmental exploration and monitoring. PLANTOIDS take inspiration from, and aim at imitating, the amazing penetration, exploration, and adaptation capabilities of plant roots."

The project has proven particularly challenging, partially because the operating systems of roots are extremely complex and difficult to replicate. "Plants roots evolve in a very complex environment; deep in the ground. They have to apply huge pressure to grow, and they only grow from the tip through what we call osmosis. They gain mass by taking water from the soil, by absorbing elements and then by expelling materials and dead cells. At the same time they produce a kind of mucus that helps them to grow and extend underground," said Barbara Mazzolai, a biologist at the Italian Institute of Technology and coordinator of the Plantoid Project.

[Credit: The Plantoid Project]

[Credit: The Plantoid Project]

In order to imitate the mechanisms of plant roots, the researchers created a robotic mechanism that would allow the machine to burrow deep into the ground in order to accumulate material with which to build new material. "Growth in nature occurs by adding material. So we tried to mimic that by developing what we called 'a growing system'. 'We feed the robot with artificial filaments and the robot is able to build its own structure and penetrate the soil. So it's able to build its own body; it's able to elongate itself, to penetrate the soil," said Ali Sadeghi, a mechanical engineer at the Italian Institute of Technology.

The robots imitate another distinctive property of plant roots: the ability to react to external stimuli, particularly by "bending," or growing away from obstacles in their search for nutrients and water in the soil. "We are mimicking this very characteristic bending in two ways. First we use electro-biological fluids. These fluids become more or less viscous depending on the electrical charge that you apply. And we also make the robot bend by overlaying (superimposing) more or less artificial material on its sides." said Mazzolai.

These robots have developed a remarkable sensitivity that rivals that of real-life organisms: "These sensors have been designed to decode and read information about the surrounding environment and external objects; the sensors sort of know when they are being touched. They are also able to understand what is the pressure and the forces they are being subjected to," said Lucia Beccai, an electronic engineer at the Italian Institute of Technology.

The applications of this technology have the potential to be extensive; the plantoids are capable of spatial analysis, as well as the detecting of nutrients, minerals, and oil for environmentalism purposes. They may even be able to assist in the detection of land mines in the ground. In the future, the researchers are also hoping to create a self-growing, flexible surgical tool, as one of the greatest obstacles in creating an adequate surgical robot is the balance between accuracy and flexibility.